@article{kombaiah_sarkar_murty_2019, title={Effect of hydriding on the creep behavior of HANA-4 zirconium alloy}, volume={767}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2019.138435}, abstractNote={HANA-4 (High Temperature Alloys for Nuclear Applications) is Zr-1.5 Nb alloy developed by the Korea Atomic Energy Research Institute for advanced nuclear fuel cladding applications. In this work, the effect of hydriding on the biaxial creep behavior of HANA-4 alloy was studied through internal pressurization of closed end tubes by applying a range of hoop stresses (27 MPa–156 MPa) at two temperatures: 400 °C and 500 °C. Test specimens included two HANA-4 tubes hydrided using an electrolytic method with 387 ppm and 715 ppm of hydrogen, respectively, and non-hydrided HANA-4 tubes as the control sample. To understand the effect of hydriding on creep, steady state creep rates and stress exponents of the specimens were determined from the creep data. Furthermore, in situ X-ray diffraction (XRD) experiments were conducted on the hydrided HANA-4 specimens during heating to detect the dissolution limit of the hydride phase. On examining the results of the creep tests and the XRD experiments collectively, it is concluded that hydrogen while being fully dissolved into the solid solution enhances the creep rate of HANA-4 tubes. On the other hand, hydrogen present, even partially, as hydride phase at the creep test temperature lowers the creep rate. The rate controlling mechanisms of creep in HANA-4, however, remained unchanged as noted from similar stress exponents of the hydrided and non-hydrided specimens. The rationale behind these observations is explained based up on models predicting the interaction of dislocations with hydrogen and hydride phase.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Kombaiah, Boopathy and Sarkar, Apu and Murty, Korukonda Linga}, year={2019}, month={Nov} }
 @article{sarkar_murty_2018, title={Anisotropic grain growth kinetics in nanocrystalline nickel}, volume={98}, ISSN={["1362-3036"]}, DOI={10.1080/09500839.2019.1583391}, abstractNote={ABSTRACT Intriguing properties exhibited by nanocrystalline metals, including a high level of mechanical strength, arise from their nanometer-scale grain sizes. It is critical to determine the evolution of grain size of nanocrystalline materials at elevated temperature, as this process can drastically change the mechanical properties. In this work, a nanocrystalline Ni foil with grain size ∼ 25 nm was annealed in situ in an X-ray diffractometer. X-ray diffraction peaks were analysed to determine the grain growth kinetics. The grain growth exponents obtained were ∼ 2–4 depending upon the crystallographic direction, indicating the anisotropic nature of the grain growth kinetics.}, number={11}, journal={PHILOSOPHICAL MAGAZINE LETTERS}, author={Sarkar, Apu and Murty, K. L.}, year={2018}, month={Nov}, pages={494–501} }
 @article{roodposhti_sarkar_murty_brody_scattergood_2016, title={Grain boundary sliding mechanism during high temperature deformation of AZ31 Magnesium alloy}, volume={669}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2016.05.076}, abstractNote={High temperature tensile creep tests were conducted on AZ31 Magnesium alloy at low stress range of 1–13 MPa to clarify the existence of grain boundary sliding (GBS) mechanism during creep deformation. Experimental data within the GBS regime shows the stress exponent is ~2 and the activation energy value is close to that for grain boundary diffusion. Analyses of the fracture surface of the sample revealed that the GBS provides many stress concentrated sites for diffusional cavities formation and leads to premature failure. Scanning electron microscopy images show the appearances of both ductile and brittle type fracture mechanism. X-ray diffraction line profile analysis (based on Williamson-Hall technique) shows a reduction in dislocation density due to dynamic recovery (DRV). A correlation between experimental data and Langdon's model for GBS was also demonstrated.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Roodposhti, Peiman Shahbeigi and Sarkar, Apu and Murty, Korukonda Linga and Brody, Harold and Scattergood, Ronald}, year={2016}, month={Jul}, pages={171–177} }
 @article{sarkar_eapen_raj_murty_burchell_2016, title={Modeling irradiation creep of graphite using rate theory}, volume={473}, ISSN={["1873-4820"]}, DOI={10.1016/j.jnucmat.2016.01.036}, abstractNote={We have examined irradiation induced creep of graphite in the framework of transition state rate theory. Experimental data for two grades of nuclear graphite (H-337 and AGOT) have been analyzed to determine the stress exponent (n) and activation energy (Q) for plastic flow under irradiation. We show that the mean activation energy lies between 0.14 and 0.32 eV with a mean stress-exponent of 1.0 ± 0.2. A stress exponent of unity and the unusually low activation energies strongly indicate a diffusive defect transport mechanism for neutron doses in the range of 3–4 × 1022 n/cm2.}, journal={JOURNAL OF NUCLEAR MATERIALS}, author={Sarkar, Apu and Eapen, Jacob and Raj, Anant and Murty, K. L. and Burchell, T. D.}, year={2016}, month={May}, pages={197–205} }
 @article{sarkar_maloy_murty_2015, title={Investigation of Portevin - Le Chatelier effect in HT-9 steel}, volume={631}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2015.02.022}, abstractNote={Portevin−Le Chatelier (PLC) effect has been observed in HT-9 steel. The present study involves different types of tensile testing to characterize the features of PLC effectin HT-9 steel. Stress serrations observed during tensile tests are analyzed using different statistical analysis techniques to investigate the underlying nature of the effect. Peaked type of stress drop distribution indicated occurrence of type B serrations in the steel. Multiscale entropy analysis of the stress serrations indicated substitutional solute atoms to be responsible for the PLC effect in HT-9 steel.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Sarkar, Apu and Maloy, Sturat A. and Murty, Korukonda L.}, year={2015}, month={Apr}, pages={120–125} }
 @article{roodposhti_sarkar_murty_2015, title={Microstructural development of high temperature deformed AZ31 magnesium alloys}, volume={626}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2014.12.064}, abstractNote={Due to their significant role in automobile industries, high temperature deformation of Mg–Al–Zn alloys (AZ31) at constant stress (i.e. creep) were studied at a wide range of stresses and temperatures to characterize underlying deformation mechanism, dynamic recrystallization (DRX) and dislocation density evolution. Various microstructures (e.g. grain growth & DRX) are noted during steady-state creep mechanisms such as grain boundary sliding (GBS), dislocation glide creep (DGC) and dislocation climb creep (DCC). Although a combination of DRX and grain growth is characteristic of low stacking fault energy materials like Mg alloys at elevated temperatures, observation reveals grain growth at low strain-rates (GBS region) along with dynamic recovery (DRV) mechanism. X-Ray Diffraction (XRD) analysis revealed a decrease in dislocation density during GBS region while it increased under dislocation based creep mechanisms which could be related to the possible DRV and DRX respectively. Scanning Electron Microscopic (SEM) characterization of the fracture surface reveals more inter-granular fracture for large grains (i.e. GBS region with DRV process) and more dimple shape fracture for small grains (i.e. DGC & DCC region with DRX).}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Roodposhti, Peiman Shahbeigi and Sarkar, Apu and Murty, Korukonda Linga}, year={2015}, month={Feb}, pages={195–202} }
 @article{sarkar_murty_2015, title={Microstructure-mechanical property correlation of cryo rolled Zircaloy-4}, volume={456}, ISSN={["1873-4820"]}, DOI={10.1016/j.jnucmat.2014.09.071}, abstractNote={The evolution of microstructure and the mechanical properties of cryo-rolled Zircaloy-4 were both investigated to understand the origin of the alloy’s strength processed at a cryogenic temperature. The correlation of dislocation density, grain size and yield stress of the rolled product indicated that an increase in dislocation density due to the suppression of dynamic recovery is the primary source of strengthening.}, journal={JOURNAL OF NUCLEAR MATERIALS}, author={Sarkar, Apu and Murty, Korukonda L.}, year={2015}, month={Jan}, pages={287–291} }
 @article{sarkar_boopathy_eapen_murty_2014, title={Creep Behavior of Hydrogenated Zirconium Alloys}, volume={23}, ISSN={["1544-1024"]}, DOI={10.1007/s11665-014-1129-y}, number={10}, journal={JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE}, author={Sarkar, A. and Boopathy, K. and Eapen, J. and Murty, K. L.}, year={2014}, month={Oct}, pages={3649–3656} }
 @article{sarkar_alsabbagh_murty_2014, title={Investigation of microstructure and mechanical properties of low dose neutron irradiated HT-9 steel}, volume={65}, ISSN={["0306-4549"]}, DOI={10.1016/j.anucene.2013.11.008}, abstractNote={HT-9 steel samples have been irradiated with fast neutrons (E > 0.1 MeV) to a low dose (1.2 × 10−3 dpa). Microstructure of the unirradiated and irradiated samples has been characterized by X-ray diffraction line profile analysis using different model-based approaches. The domain size and density of dislocations of the irradiated steel have been estimated. Different types of tensile tests have been carried out at room temperature to assess the changes in mechanical properties of HT-9 steel due to neutron irradiation.}, journal={ANNALS OF NUCLEAR ENERGY}, author={Sarkar, A. and Alsabbagh, A. H. and Murty, K. L.}, year={2014}, month={Mar}, pages={91–96} }
 @article{alsabbagh_sarkar_miller_burns_squires_porter_cole_murty_2014, title={Microstructure and mechanical behavior of neutron irradiated ultrafine grained ferritic steel}, volume={615}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2014.07.070}, abstractNote={Neutron irradiation effects on ultra-fine grain (UFG) low carbon steel prepared by equal channel angular pressing (ECAP) have been examined. Counterpart samples with conventional grain (CG) sizes have been irradiated alongside with the UFG ones for comparison. Samples were irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) to 1.37 dpa. Atom probe tomography revealed manganese and silicon-enriched clusters in both UFG and CG steel after neutron irradiation. Mechanical properties were characterized using microhardness and tensile tests, and irradiation of UFG carbon steel revealed minute radiation effects in contrast to the distinct radiation hardening and reduction of ductility in its CG counterpart. After irradiation, micro hardness indicated increases of around 9% for UFG versus 62% for CG steel. Similarly, tensile strength revealed increases of 8% and 94% respectively for UFG and CG steels while corresponding decreases in ductility were 56% versus 82%. X-ray quantitative analysis showed that dislocation density in CG increased after irradiation while no significant change was observed in UFG steel, revealing better radiation tolerance. Quantitative correlations between experimental results and modeling were demonstrated based on irradiation induced precipitate strengthening and dislocation forest hardening mechanisms.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Alsabbagh, Ahmad and Sarkar, Apu and Miller, Brandon and Burns, Jatuporn and Squires, Leah and Porter, Douglas and Cole, James I. and Murty, K. L.}, year={2014}, month={Oct}, pages={128–138} }
 @misc{roodposhti_sarkar_murty_scattergood, title={Effects of microstructure and processing methods on creep behavior of AZ91 magnesium alloy}, volume={25}, number={9}, journal={Journal of Materials Engineering and Performance}, author={Roodposhti, P. S. and Sarkar, A. and Murty, K. L. and Scattergood, R. O.}, pages={3697–3709} }